Liquid flow control valve

ABSTRACT

A flow control valve in which a moisture expansible body (18) is adapted to close a bleed valve (24) shutting off a bleed from an inlet chamber (2) through a by-pass (12) to the underside of a thrust plate (9) operatively coupled by a rod (9) to a valve member (26) arranged to close communication between the inlet (2) and an outlet (4) chamber. On absorption of moisture, the body (18) expands to drive thrust rod (21) downwards to close the bleed valve (24) whereby pressure under the thrust plate (9) is relieved and inlet water pressure closes valve member (26) to cut off discharge. On drying the body (18) shrinks relieving thrust rod pressure on the valve (24) which opens under inlet pressure and pressure liquid is bled through passages (25) and the by-pass (12) to drive the thrust plate (9) upwards to open valve member (26) and allow liquid flow from the inlet (2) to the outlet (4) chamber and to discharge (5). The expansible body (18) may be moistened by ambient moisture or controlled wetting may take place by a bleed (14) from the outlet chamber (4) leading via an adjustable throttle valve (15) into an apertured casing (17) containing the body (18) of expansible material.

This invention concerns a liquid flow control valve and particularly toa liquid flow control valve without the need for manual actuation.

Flow control valves are known in which servo control of the valve ispossible using electrical or electronic means responding to a signalgenerated in response to a variable condition, for example a conditionvaried by the flow of 1iquid through the valve.

It is also known in a water cistern to control the level of water by aball-cock having a ball floating on the water in the cistern and openingand closing the ball-cock according to variations in water level, theball-cock controlling the flow of liquid into the cistern.

It is known from GB-845014 to provide a water responsive actuator forautomatically inflatable lifesaving equipment in which a spring loadedplunger is held in a cocked position by a latch held in position by athrust rod displaceable out of latching position by a stack ofwasher-like members disposed on the thrust rod and expansible onimmersion to drive the rod out of a latching condition. This allowsrelease of the plunger under spring force to operate a gas bottle torelease gas.

It is known from U.S. Pat. No. 3,874,590 to provide a flow control valveoperatively coupled to a moisture sensing element comprising a stack ofmoisture sensitive material operating a plunger against a spring loadedball valve such that on drying of the material the plunger drives theball against the spring and on moistening of the material the ball isdriven by the spring. Under spring action the ball closes a by-pass whenthe material is wet, and the control valve is closed under supply waterpressure. When the material is dry the ball is displaced to open theby-pass and a pressure signal from the water supply through the by-passaugments a spring pressure on a valve member to exceed supply pressureon an opposite side of the valve member to move the valve member to anopen condition.

It is known from DE-A-2 513 600 to provide a flow control valve with amoisture sensitive control comprising a moisture expansible tubularmember arranged on expansion to release a valve member which allowssupply pressure to a closure diaphragm arranged to close a dischargeoutlet from the control valve. On drying of the expansible member itshrinks and drives the valve member to a closed condition whereby waterpressure on an underside of the diaphragm opens the discharge of thecontrol valve.

It is an object to provide an improved flow control valve embodying amoisture expansible control member.

A control valve according to the invention comprises a valve body havinga liquid inlet leading to an inlet chamber and a liquid outlet leadingfrom an outlet chamber, the inlet and outlet chambers communicating by aflow passageway closeable by a valve plate having one side facing theinlet chamber and the other arranged sealing to engage a valve seat toclose the passageway, a thrust member extends from the valve plate awayfrom the inlet chamber and being supported for opening and closingmovement of the valve plate. Distal from the valve plate the thrustmember is provided with a thrust plate disposed in a chamber adapted toreceive fluid at pressure on a side of the thrust plate opposite thevalve plate to drive the valve plate to an open condition. The inletchamber communicates with by-pass means via a valved passage comprisinga valve member moveable under liquid pressure in the inlet chamber to anopen condition to allow flow of liquid through the bypass, and closeablefrom outside the inlet chamber, the by-pass leading to the liquidchamber to operate the thrust plate to open the valve plate, and meansfor closing the valve member comprising a control member including athrust rod and a moisture expansible body arranged on ex pansion todrive the thrust rod to drive the valve member to a closed condition andon shrinking to release the valve member

In one arrangement the thrust plate and the liquid receiving chamber areseparated by a resilient or flexible diaphragm sealing a liquidreceiving space from the thrust plate, the arrangement being such as toallow movement of the thrust plate between open and closed conditions ofthe valve plate.

Advantageously the control member is arranged and adapted to close thevalve member when the body of absorbtive material is wet and to allowopening of the valve member, under the influence of water pressure inthe inlet chamber when the body dries. Suitably the body is adapted tobe exposed to an external source of moisture, for example an overheadsprinkler system supplied with water flowing from the outlet so thatafter an interval during which the absorptive material absorbssufficient water to expand to close the valve member, the by-pass supplyto the thrust plate is cut off, and the valve plate closes under theinfluence of pressure in the inlet chamber to cut off the supply ofwater to the sprinkler system. This cuts off exposure of the body ofwater responsive material to water and the body may be allowed to dry byatmospheric evaporation until such contraction takes place that waterpressure in the inlet chamber opens the valve member to allow flowthrough the by-pass to the chamber beneath the diaphragm to operate thethrust member by force on the thrust plate to unseal the valve plate andallow flow from the inlet chamber into the outlet chamber.

As an alternative or in addition the body of expandable material may beexposed to liquid bled from the outlet chamber through an adjustablethrottle controlled bleed whereby the time that the expandable bodytakes to expand to close the valve member may be controllably varied. Tothis end a bleed tube comprises an adjustable throttle valve with a tubeportion leading therefrom to the body to direct bled liquid thereonto.Suitably the tube portion is flexible so that it may be bent over andinserted into an aperture in a cap covering the body of expandablematerial.

In order to allow the body of expandable material to be exposed toambient conditions it is suitably contained within an apertured casingmounted on the valve body.

The invention will now be described by way of example with reference tothe accompanying partly diagrammatic drawings in which:

FIG. 1 is a side elevation of a control valve according to theinvention;

FIG. 2 is a cross-section taken on line 2--2 of FIG. 1,

FIG. 3 is a partially exploded perspective of a valve member and waterresponsive body of the valve of FIGS. 1 and 2, and

FIG. 4 is a cross-section similar to that of FIG. 2 of part of amodified valve.

A valve body comprises a cylindrical member 1 having the inlet chamber 2and inlet 3 thereto disposed above an outlet chamber 4 and an outlet 5therefrom, a thrust member 6 extending downwardly through the outletchamber 5 through a bushing 7 to a thrust plate 9 disposed above adiaphragm 8 in a chamber 10 at the lower end of the cylindrical body 1and closed by a lower removable closure plate 11. A by-pass 12 extendsbetween the inlet chamber 2 and the lower closure plate 11 externally ofthe cylindrical body 1, the closure plate 11 being formed with a by-passpassageway part 12A leading to a central aperture 12B below thediaphragm 8 within a recessed portion of the closure plate 11 facing thediaphragm 8. A bleed passage 13 extends from the outlet chamber to ableed tube 14 externally of the body 1 and extending upwardly from thebleed passage 13 and is formed with an adjustable throttle valve 15 tocontrol the bleed flow. A suitable throttle valve is disclosed EP-A-0084 938. A flexible bleed tube portion 16 extends upwardly from thethrottle 15 to the region of an upper cap 17 defining a casing for abody 18 of liquid expandable material. The casing 17 is releasablyclosed at its upper end with a threaded plug 19A having a centralaperture 20A forming a sliding guide for an upper end of the plunger 21carrying the body 18, and a series of further apertures 20B for theadmission of ambient liquid through the casing to the body. The upperextremity of the flexible tube portion 16 may be inserted into one ofthese further apertures 20B to direct the bled liquid onto theexpandable body 18.

Below the plug 19A the cap-like casing 17 surrounds the body 18 ofexpandable material and is formed with a series of enlarged sideapertures 22 for ambient exposure of the body 18 of expandable material.

The lower end of the casing 17 is substantially closed and that isformed centrally with an upright bore 20C within which a central lowerspigot of a button valve 24 is freely floating, the button of the buttonvalve being arranged sealingly to engage an upper side of the lower endof the casing 17. A plug 19B is releasably secured within the casing 1above the button valve 24 to define below the plug 19B and the closedlower end of the casing 1 a chamber 23 communicating with lateral bleedpassages 25 extending radially outwards through the casing 1. The plug19B is formed centrally with a bore 20B forming a sliding guide for alower end of the thrust member 21 which is arranged to engage the buttonof the button valve 24 on an upper side. The lower side of the plug 19Bis spaced above the lower end of the casing 1 sufficiently to allow freefloating movement of the button therebetween whilst the button spigotloosely guides the button in the bore 20C and allows flow communicationthrough the bore 20C to the chamber 23 when the button is lifted fromsealing engagement with the lower end of the casing. The arrangement issuch that downward movement of the thrust rod 21 closes the button ofbutton valve 24 against its seating to cut off said flow communication.

The closed lower end of the cap-like housing 17 is releasably mounted inthe upper end of the cylindrical valve body 1 in a fluid tight mannerwith the bleed passages 25 of the cap member communicating with a bleedpassage 25A through the wall of the valve body 1 and communicating withthe by-pass 12. To this end a pair of axially spaced annular seals 27,28are disposed between the lower end of the casing 17 and the body 1 todefine therebetween an annular chamber 29 communicating with the bleedpassage 25 and the bleed passage 25A in communication with the by-pass12.

The body of expandable and contractable material 18 comprises a stack ofabsorbant washers 18A mounted on the thrust rod 21 above a pressureplate 21A secured thereto intermediate its ends, and with gridlikespacers 18B to admit flow of liquid radially into the stack. The thrustrod 21 extends downwardly from the pressure plate 21A supporting thewashers and slidably engages the upper bore portion 20C in the closedlower end of the cap-like casing 17. The height of the stack of washers18 is such that with the upper end engaging the underside of the closureplug 19A and the washer being dry the button valve 24 may be lifted fromits seating by liquid pressure in the inlet chamber 2 to allowcommunication between the inlet chamber 2 and the by-pass 12, and withthe washers 18A in a wet expanded condition the lower end of the plunger21 drives the button valve 24 against its lower seating to close theinlet chamber 2 from the chamber 23 and from the by-pass 12. By virtueof the threaded assembly of the closure plug 19A with the casing 17 ameasure of adjustment for setting purposes is provided.

The arrangement is also such that on removal of the casing 17 from thecylindrical body 1 access may be had through the inlet chamber to avalve plate 26 which may be a resilient tap washer assembly releasablysecured at the upper end of the thrust member 6, for withdrawal andreplacement purposes.

The thrust plate 9 at the lower end of the thrust member 6 is of largerdiameter than the valve plate 6 or tap washer to facilitate lifting, andthe thrust member 6 is suitably mounted in a friction bearing adapted togive a friction resistance to movement of about 11/2lbs (680 grams). Tothis end the thrust member 6 may be slidably mounted between a pair ofspaced O-rings supported in the bushing 7.

A vent 10A is provided through the cylindrical body wall from the lowerchamber 10 above the diaphragm 8 to allow venting of any liquid whichmay pass the O-rings from the outlet chamber 5.

Whilst a variety of materials may be used for the washer it is desirablethat the characteristics of expansion and contraction are reliablyrepeatable over protracted periods of exposure. A suitable commerciallyavailable paper-like material has been found to be suitable and it hasthe capability of expanding a stack to about 50% of its dry height andto return to its dry height with an accuracy of about 1 thousandth of aninch in a stack of about 1/2 inch dry height (2.54×10⁻³ cm in 1.27 cm).

In use the inlet 3 is suitably connected to a water supply at pressureand the outlet to a discharge pipe which may, for example, lead to awatering system such as a water sprinkler.

With the body 18 of washers 18A in a dry condition the water pressure inthe chamber 2 lifts the button valve 24 and water is bled through thechamber 23, the bleed passages 25 and 25A to the by-pass 12 to theunderside of diaphragm 8 and pressure is applied to the underside ofplate 9 in opposition to pressure in the inlet chamber 2 above the valveplate 26, and due to the larger area of plate 9 the valve plate 26 islifted from its seating to allow communication between the inlet chamber2 and outlet chamber 4 and flow to the outlet 5 to discharge.

Flow will also occur through the bleed tube 14 and via the throttlevalve 15 and the flexible tube 16 through the cap member onto thewashers 18A at a rate controlled by the setting of the throttle valve15. A moisture is absorbed by the washers 18A, the stack will expandbetween the upper plug 19A and the thrust rod pressure plate 21A todrive the rod 21 downwards against the button valve 24 to seat thebutton against the lower end of the casing 17 to shut off bleed flowfrom the inlet chamber 2 via the chamber 23 and by-pass 12 to theunderside of the pressure plate 9. As a result pressure in the inletchamber 2 drives the valve plate 26 on to its seating to shut off flowto the outlet chamber 4 and through the outlet 5 to discharge.

Discharge flow is thus cut off until the body 18 dries and shrinkssufficiently to allow inlet chamber water pressure to lift the buttonvalve 24 and recycle the above described operation.

By suitable adjustment of the throttle valve 15 to regulate the wettingflow to the body 18, the time during which the valve is closed can becontrolled. The time taken for the body 18 to dry sufficiently to allowlifting of the button valve 24 will determine the shut off period beforerecycling, and to a limited degree this may be adjusted by adjustment ofthe axial position of the upper screwed plug 19A.

As an alternative or in addition to the moistening of the body 18 by thebleed 14,15,16, the valve assembly may be exposed to the water dischargefrom the outlet 5, for example in the path of discharge of a sprinklersystem so that the body 18 is moistened by the main discharge andresponds thereto to control the valve operation.

An advantage of the above described arrangement is that the valve ispositively shut off by direct closure of the button valve underexpansion of the body 18 and the resultant imbalance of water pressureon the valve plates 9, 26 so that risk of excess discharge through thevalve due to malfunction is minimised.

In a modification shown in FIG. 4 in which like reference numerals areused for corresponding parts in FIGS. 1-3 the lower plug 19B is formedwith a lower cylindrical extension 30 forming a sliding guide for thelower elongate portion of the thrust rod 21 and having intermediate itsupper and lower ends an annular flange 31 which sealingly engages aseating at the lower end of the casing 17 to define below the plug 19Band around the extension 30 above the flange 31 a chamber 23. Bleedbores 32 extend through the extension 30 above the flange 31 and anO-ring 33 is mounted on the extended rod 21 so that on expansion orcontraction of the body 18 the O-ring moves downwardly or upwardly pastthe bleed bore 32 to close or open the chamber 23 from or intocommunication with the inlet chamber 2. The O-ring 32 serves thepreviously described function of button valve 24 which is omitted fromthis embodiment.

I claim
 1. A liquid flow control valve comprising:a valve body (1)defining a fluid inlet (3) leading to an inlet chamber (2), and a fluidoutlet (5) leading from an outlet chamber (4), the inlet and outletchambers (3,4) communicating by a flow passageway; a valve plate (26)disposed within said body having one side facing the inlet chamber (2)and the other arranged sealingly to engage a valve seat defined by saidpassageway to close the passageway; said body defining a thrust chamber(10) opposite the inlet chamber from the outlet chamber and connected toreceive fluid at pressure from the fluid inlet; a thrust member (6)extending from the valve plate (26) away from the inlet chamber (2) andbeing supported for opening and closing movement of the valve plate(26), the thrust member having a distal end from the valve plate (21); athrust plate (9) connected to the thrust member and disposed in thethrust chamber to receive fluid at pressure on a side of the thrustplate (9) opposite the valve plate (26) to drive the valve plate (26) toan open condition; by-pass means communicating with the inlet chamberand including a valved passage (24), a by-pass passage (22) leading fromthe valve pasage, and a valve member (24) disposed in the valve passagemovable under fluid pressure in the inlet chamber (2) to an opencondition for allowing flow of fluid through the by-pass passage (12),and closeable from outside the inlet chamber (2), the by-pass passage(12) leading to the thrust chamber (10) to operate the thrust plate (9)to open the valve plate (26); and means for closing the valve member(24) including a control member having a moisture expansible body (18)secured within the valve body and a thrust rod (21) located in contactwith the expansible body, the expansible body arranged on expansion todrive the thrust rod (21) to drive the valve member (24) to a closedcondition and on shrinking to release the valve member (24).
 2. A valveas claimed in claim 1, further comprising a resilient diaphragm disposedwithin the valve body to separate the thrust plate (9) and the thrustchamber (10).
 3. A valve as claimed in claim 1, further comprising anadjustable throttle controled bleed (13, 14,16) connecting the outletchamber and the moisture expansible body, whereby the time that theexpansible body (18) takes to expand to close the valve member (24) maybe controllably varied.
 4. A valve as claimed in claim 1, furthercomprising an apertured (22) cap-like casing (17) mounted on the valvebody (1) and containing said expansible body to expose the expansiblebody (18) to ambient conditions.
 5. A valve as claimed in claim 4,further comprising a pressure plate (21A) secured to the thrust rod(21), the expansible body (18) being mounted within the casing (17) andarranged to act on the pressure plate.
 6. A valve as claimed in claim 5,wherein the expansible body (18) includes a stack of washer-like layers(18A) mounted on the thrust rod (21).
 7. A valve as claimed in claim 6,wherein the expansible body further includes grid-like spacers (18B)mounted on the thrust rod (21) to facilitate flow of liquid into thestack.
 8. A valve as claimed in claim 1, wherein the valve member (24)includes a button valve having a lower spigot, and the valved passagecommunicates with the inlet chamber and a bleed chamber (23), the lowerspigot being freely slidable within the valved passage and the buttonbeing freely floating in the bleed chamber (23) in the path of thethrust rod (21), whereby expansion of the expansible body (18) drivesthe thrust rod (21) to seat the button valve (24) to close the valvedpassage (20C).
 9. A valve as claimed in claim 1, wherein the valvemember (24) includes an O-ring (33) mounted on the thrust rod (21) andmovable therewith in sealing engagement with the valved passage, foropening and closing a bleed aperture defined in the valve body andleading to the bleed chamber (23) defined in the valve body andcommunicating with the by-pass passage(12).